Electronic communication systems provide for distribution and exchange of information between system connection points among nodes by modulating an electromagnetic signal to have a particular state in a given coding state space, or to pass through particular changes in states, the state or change in state(s) representing a particular symbol, each symbol encoding one or more bits of information, and then propagating the modulated signal over wireless links and/or through non-wireless transmission paths such as, for example, printed circuit board (PCB) traces, repeater/amplifiers, multiplexers and other switches, to arrive at various destinations.
Switches within an electronic communication system may include Q:R switches, meaning Q inputs and R outputs, where Q and R may or may not be equal to one another. For example, a 1:2 switch may have one input line, or one multi-line input bus, and two output lines, or two multi-line output busses.
A typical Q:R switch circuit fabricated in conventional technology is a single integrated circuit (IC) chip, the IC chip having conducting input/out (I/O) terminals that are connected to particular circuit terminal points (e.g., R buffer outputs, Q buffer inputs, VCC, GND, and control lines) via IC internal conductor traces. The IC chip is typically mounted in a package, the package having external conducting terminals for connection to, for example, a printed circuit board (PCB) and the package having internal conducting terminals connected to the package's external conducting terminals via, for example, conductor traces in the package. Each of the package internal conducting terminals is, in turn, connected, via one of several known conductor means, to one or more corresponding chip I/O terminals.
One means for connecting the package internal terminals to the IC chip I/O terminals consists of a plurality of thin conducting wires, each bond wire bonded at one end to the one of the IC chip I/O terminals and bonded at the other end to one of the package internal terminals. This means is referred to as “bond wire.” In typical bond wire arrangements, the IC chip I/O terminals and the package internal I/O terminals have both a configuration and a material that is particularly suited to bonding to the wire. These terminals are generically referenced in this description as “bond pads.”
As integrated circuit (IC) processes have advanced, feature sizes have become smaller and, in turn, this has allowed practical implementation of entire functions, e.g., Q:R switches, on a single die. Further, the smaller feature sizes provided by advances in IC technology not only permit forming the entire circuit on a single die but, also, have reduced the dimensions and area of the die. Conventional design practice has therefore employed these advances in IC technology, in accordance with its conventional approach to providing increased density and increased bandwidth, to implement functions having a plurality of high bandwidth input/output lines such as, for example, Q:R switches and other similar and equivalent circuits, on a single IC die.
The present inventors have identified, though, that the single die solutions to density and cost objectives, particularly combined with standardized packages have inherent shortcomings including, for example, a not readily controllable I/O port impedance, with related shortcomings including, for example, skew and impedance mismatch.